Comment 2 for bug 1577721

Two events detected by ovsdb-client almost at the same time:
2016-05-02 23:03:14.007 2686 DEBUG neutron.agent.linux.async_process [-] Output received from [ovsdb-client monitor Interface name,ofport,external_ids --format=json]: {"data":[["b13d9fa2-73ff-474b-9d4d-5c651a794201","delete","qvo62f4fa37-a1",-1,["map",[["attached-mac","fa:16:3e:9b:04:3b"],["iface-id","62f4fa37-a181-4db4-8db7-ed12552af141"],["iface-status","active"],["vm-uuid","b739f239-702e-402a-a5b6-815926afc82f"]]]],["61beda06-8062-4176-bca5-11a1378e0b26","insert","qvo62f4fa37-a1",["set",[]],["map",[["attached-mac","fa:16:3e:9b:04:3b"],["iface-id","62f4fa37-a181-4db4-8db7-ed12552af141"],["iface-status","active"],["vm-uuid","b739f239-702e-402a-a5b6-815926afc82f"]]]]],"headings":["row","action","name","ofport","external_ids"]} _read_stdout /usr/lib/python2.7/site-packages/neutron/agent/linux/async_process.py:236

2016-05-02 23:03:14.008 2686 DEBUG neutron.agent.linux.async_process [-] Output received from [ovsdb-client monitor Interface name,ofport,external_ids --format=json]: {"data":[["61beda06-8062-4176-bca5-11a1378e0b26","old",null,["set",[]],null],["","new","qvo62f4fa37-a1",2,["map",[["attached-mac","fa:16:3e:9b:04:3b"],["iface-id","62f4fa37-a181-4db4-8db7-ed12552af141"],["iface-status","active"],["vm-uuid","b739f239-702e-402a-a5b6-815926afc82f"]]]]],"headings":["row","action","name","ofport","external_ids"]} _read_stdout /usr/lib/python2.7/site-packages/neutron/agent/linux/async_process.py:236

meaning that port qvo62f4fa37-a1 was deleted and created right away.

ovs agent in each loop processes all added ports first and then all deleted ports. In this case it was the same port so it was added first and then removed. Not sure what caused such behavior. It's probably some race due to server and agent node being out of sync. More investigation needed.